sdiahci, sdodin: avoid calling kproc() while holding ilock()

[plan9front.git] / sys / src / lib9p / post.c

diff --git a/sys/src/lib9p/post.c b/sys/src/lib9p/post.c
index b42c7b32cd865ff3be54be360cde0005e101218a..8abddfbd10f5226cfcb10b537e1c53caac7ace3b 100644 (file)
--- a/sys/src/lib9p/post.c
+++ b/sys/src/lib9p/post.c
@@ -56,6 +56,56 @@ _postmountsrv(Srv *s, char *name, char *mtpt, int flag)
                close(s->srvfd);
 }
 
+void
+_postsharesrv(Srv *s, char *name, char *mtpt, char *desc)
+{
+       int fd[2];
+
+       if(!s->nopipe){
+               if(pipe(fd) < 0)
+                       sysfatal("pipe: %r");
+               s->infd = s->outfd = fd[1];
+               s->srvfd = fd[0];
+       }
+       if(name)
+               if(postfd(name, s->srvfd) < 0)
+                       sysfatal("postfd %s: %r", name);
+
+       if(_forker == nil)
+               sysfatal("no forker");
+       _forker(postproc, s, RFNAMEG);
+
+       /*
+        * Normally the server is posting as the last thing it does
+        * before exiting, so the correct thing to do is drop into
+        * a different fd space and close the 9P server half of the
+        * pipe before trying to mount the kernel half.  This way,
+        * if the file server dies, we don't have a ref to the 9P server
+        * half of the pipe.  Then killing the other procs will drop
+        * all the refs on the 9P server half, and the mount will fail.
+        * Otherwise the mount hangs forever.
+        *
+        * Libthread in general and acme win in particular make
+        * it hard to make this fd bookkeeping work out properly,
+        * so leaveinfdopen is a flag that win sets to opt out of this
+        * safety net.
+        */
+       if(!s->leavefdsopen){
+               rfork(RFFDG);
+               rendezvous(0, 0);
+               close(s->infd);
+               if(s->infd != s->outfd)
+                       close(s->outfd);
+       }
+
+       if(mtpt){
+               if(sharefd(mtpt, desc, s->srvfd) < 0)
+                       sysfatal("sharefd %s: %r", mtpt);
+       }else
+               close(s->srvfd);
+}
+
+
 static void
 postproc(void *v)
 {